The Arizona sentinel., 1887-06-25

the cluster Tn Hercules, we should find
 that its stars, as seen from distance
 of 5000, ,000 600 miles. their average
 distance apart, would shine 1, 400 times
 as bright as Sirius shines in our sky.
 Sirius is probably 800 times as bright
 as the faintest star that the naked eye
 perceives on a clear night Then
 imagine a star three times as much
 brighter than Sirius as Sirius is
 brighter than the smallest star you
 can see, and you will have some notion
 of the brilliancy of the stars in ques-
 tion as seen from one another.
 Now let us suppose a world revolv- ing around a star situated at the cen
 ter of the cluster. Assuming that the
 surrounding stars are arranged in a
 pretty symmetrical way, there would
 be dozen of them within a distance
 of 5000, ,OO0,O miles. and each of these would, as seen from the world at
 the center, appear 1, 400 times brighter
 than Sirius appears to us There
 would be upward of 50 stars twice as
 far away, each of which would be $50
 times as bright as Sirius. Thus the
 stars of the cluster, as seen from the
 center. would go on increasing in
 number and diminishing in brightness,
 but as the total number is limited to
 IA, 900 or 15, 900, the outermost stars
 would be approximately 1S5, ,000, ,000, 900 miles away, and each would shine six
 times as bright as Sirius.
 It is apparent that there would be sort of perpetual daylight at the cen- ter of such congregation of suns. Let us see about how bright this light would be. Of course. our suppositi- tious planet might receive from the sun to which it belonged as brilliant a daylight as our sun gives to us, but what would be the illumina- tion of it's nights, or, in other words, of that side of it which was turned away from its sun? Zollner has esti- mated the light of the sun to be 61S,040 times as great as that of the full moon. This, upon the estimate of Sirius light as compared with the suns that we have adopted, would give the moon about 5000 times as much light as Sirius.
 Since each of the stars in the cluster has 1.400 times the light of Sirius, at 5000, ,000. 900 miles distance, and there are dozen of them within that dis tance of the centre. it follows that these dozen stars will shed above twice as much light upon world in the centre of the cluster as the full moon sends to us. And, since the light re- ceived from body varies inversely as the square of its distance, while the number of such bodies arranged in the roughly spherical way we have sup posed would increase directly as the square of their distance from inc cen tre, it is clear that the amount of light received from the whole cluster would be as many times amount received from the twelve stars nearest the center, as the radius of the cluster exceeds 5000, 900, 900 miles. This would be about fifteen times, and so the total amount of light shed upon the center would be fifteen times the amount shed from the first twelve stars, or about thirty times the amount that the full moon pours upon the earth. But only half the stars of the cluster would be above the horizon at once, and so the illumlnation of the night sky on our imaginary world would be fifteen times as bright as the light of the full moon upon the earth.
 The number of stars visible to us with the unaided eye on a clear night is not over 5000. and the great ma jority of these are so faint that they require some attention to be seen at all. How contemptible, then, IS the starry Armament presented to us in comparison with the glorious heavens in this sun cluster of Hercules, where more than twice as many stars as we can see blaze nightly with radiance so brilliant that the faintest of the m are six times as bright as the greatest star in our sky.
 Indeed, the light of all these aston- ishingly bright stars diffused in the at of our imaginary planet would be so great as largely to rob the individual stars of their brilliance, just as the light of the moon or the blaze of the electric lights upon the Brooklyn bridge serves to partially efface the stars in our sky.
 Another effect of this splendid dis play of stars would be to shut out from the view of the inhabitants of the cen ter of the cluster, all the outside uni verse. In the food of light poured from the members of the cluster the other stars beyond them would be in- and the dwellers within the system would be, so to speak, shut up in little universe of their own, know ing nothing of the greater universe be- yond, in which we see their cluster floating like a mote Tn the sunbeams.
 It remains to consider briefly what would be the condition of things upon a world circling around one ofthe stars at the outer edge of the cluster. Here, as a moments thought shows the presented would be very different from those at the center of the cluster. Less than half of the sky visible from such planet would be occupied by the brilliant stars of the cluster, while the other half would be, so to speak, open